Volumetric meters are commonly used in agricultural seeding implements such as grain drills and air seeders to meter the seed. Volumetric meters are also used with fertilizer applicators. A volumetric meter often employs a meter roller contained within a housing that defines an inlet for receiving product from a tank, typically located above the meter roller, to feed seed into the housing by gravity. The meter roller is fluted so that as the roller is rotated, product from the tank is carried to an outlet in a controlled manner based on the size of the roller flutes and speed of rotation of the roller. From the meter housing, the seed is carried by a distribution system for dispensing to the soil. The distribution system typically includes a number of individual channels each receiving seed from a defined section of the meter roller. The meter roller is typically constructed of multiple roller segments mounted on a common drive shaft. Each roller segment directs product to an individual channel of the distribution system. The distribution system may be a gravity system that guides the seed as it falls downward from the meter to the soil. Alternatively, the distribution system may be pneumatic, using air flow to distribute the seed from the meter. A pneumatic system may also further divide the seed delivered from one roller segment into multiple, individual row distribution tubes.
In contrast to a volumetric seed meter, row crop planters use individual seed meters located at each row unit. These meters are supplied by either individual seed hoppers mounted to the row unit or supplied with seed from a central tank, often with a pneumatic system to deliver the seed. The seed meters, however, instead of metering the seed based on volume, singulate the seed and delivers a predetermined number of seeds, typically one, upon specified time/distance intervals. Recent products have been made available on row crop planters that enable the flow of seed to be shut-off at the individual row units. This is often accomplished by a clutch mechanism in the seed meter drive that is actuated to disengage the seed meter drive. An example of such is shown in U.S. Pat. No. 7,571,688. These have met with commercial success as customers seek to control costs by eliminating any double seeding which can occur at the edge of a field when the area remaining area to be seeded is not as wide as the planter or in a non-rectangular field where the rows do not all end at the same location or when crossing waterways that are not to be seeded. Since the seed shut-off is at the individual meter mounted on the row, there is only a short or no delay from the time the meter is shut-off to stoppage of the seed flow at the soil.
To provide a similar shut-off on an air, i.e. pneumatic, seeder, however, a number of unique challenges must be overcome that do not exist with a row crop planter. These challenges include: 1) if seed is stopped from flowing into the meter roller, there is a long delay until seed stops flowing at the discharge since the meter housing must empty before seed flow stops; 2) air seeders may mix multiple products within the airstream so that stopping the flow of seed to the ground by redirecting the flow after the seed is introduced into the air stream requires separation of the mixed products; 3) with some air seeders, the product tanks are pressurized during operation, further complicating the return of redirected product to the tank; and 4) if product flow from the meter roller is stopped but the roller continues to rotate, there is the possibility of damage to seed that is trapped in the roller.
One approach to providing a sectional meter shut-off in an air seeder is shown in US patent application publication number 2009/0079624, published Mar. 26, 2009. Slidable gates are positioned between the product storage tank and the meter roll. Individual actuators are provided to move each gate between open and closed positions. Because the gates are positioned between the storage tank and the meter, after activation of the shut-off actuators, product will continue to flow until the meter is emptied of product. This arrangement does nothing to address the first challenge listed above.
It is also known to in the context of a grain drill to provide a clutch axially adjacent at least one roller segment to stop one row from planting to create a tramline in a field as shown in U.S. Pat. No. 5,078,066. This approach, since the clutch is axially adjacent the roller segment can not be used in a meter roller where the roller segments are adjacent one another or closely spaced by divider walls that separate product flow into channels as the product enters the meter.